1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_FUTEX_H
3 #define _LINUX_FUTEX_H
4
5 #include <linux/sched.h>
6 #include <linux/ktime.h>
7
8 #include <uapi/linux/futex.h>
9
10 struct inode;
11 struct mm_struct;
12 struct task_struct;
13
14 /*
15 * Futexes are matched on equal values of this key.
16 * The key type depends on whether it's a shared or private mapping.
17 * Don't rearrange members without looking at hash_futex().
18 *
19 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
20 * We use the two low order bits of offset to tell what is the kind of key :
21 * 00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
22 * (no reference on an inode or mm)
23 * 01 : Shared futex (PTHREAD_PROCESS_SHARED)
24 * mapped on a file (reference on the underlying inode)
25 * 10 : Shared futex (PTHREAD_PROCESS_SHARED)
26 * (but private mapping on an mm, and reference taken on it)
27 */
28
29 #define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */
30 #define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
31
32 union futex_key {
33 struct {
34 u64 i_seq;
35 unsigned long pgoff;
36 unsigned int offset;
37 } shared;
38 struct {
39 union {
40 struct mm_struct *mm;
41 u64 __tmp;
42 };
43 unsigned long address;
44 unsigned int offset;
45 } private;
46 struct {
47 u64 ptr;
48 unsigned long word;
49 unsigned int offset;
50 } both;
51 };
52
53 #define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = 0ULL } }
54
55 #ifdef CONFIG_FUTEX
56 enum {
57 FUTEX_STATE_OK,
58 FUTEX_STATE_EXITING,
59 FUTEX_STATE_DEAD,
60 };
61
62 static inline void futex_init_task(struct task_struct *tsk)
63 {
64 tsk->robust_list = NULL;
65 #ifdef CONFIG_COMPAT
66 tsk->compat_robust_list = NULL;
67 #endif
68 INIT_LIST_HEAD(&tsk->pi_state_list);
69 tsk->pi_state_cache = NULL;
70 tsk->futex_state = FUTEX_STATE_OK;
71 mutex_init(&tsk->futex_exit_mutex);
72 }
73
74 void futex_exit_recursive(struct task_struct *tsk);
75 void futex_exit_release(struct task_struct *tsk);
76 void futex_exec_release(struct task_struct *tsk);
77
78 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
79 u32 __user *uaddr2, u32 val2, u32 val3);
80 #else
81 static inline void futex_init_task(struct task_struct *tsk) { }
82 static inline void futex_exit_recursive(struct task_struct *tsk) { }
83 static inline void futex_exit_release(struct task_struct *tsk) { }
84 static inline void futex_exec_release(struct task_struct *tsk) { }
85 static inline long do_futex(u32 __user *uaddr, int op, u32 val,
86 ktime_t *timeout, u32 __user *uaddr2,
87 u32 val2, u32 val3)
88 {
89 return -EINVAL;
90 }
91 #endif
92
93 #endif
94
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.